Engine-drive



qu m w Patented Nov. 29, i921,

INVENT'EIR ATTEIHNEYS EUGENE A. FORD,` OIE1 NEWTON, MASSACHUSETTS,ASSIGNOR TO R. E. D. ENGNE COMPANY, ING., OF yNEW YORK, N. Y., ACORPORATION OF NEW YORK.

ENGINE-DRJEVE.

Lacasse.

Specification of Letters Patent.

Application led March 14, 1921. Serial No. l52,362.

To all whom t may cof/wem.'

Be it known that I, EUGENE A. F ORD, a citizen of the United' Statesresiding at Newton, in the county of' iddleseX and State ofMassachusetts, have invented new and useful Improvementsin,Engine-Drives, of which the following is a specification.

The present invention relates to engines of the reciprocating type, andconversely is applicable to pumps of vsimilar type. It will be describedin the following specification in terms of its application to aninternal combustion engine, but the scope in which I claim protection isnot limited to that particular use.

The object of the invention is to provide in a reciprocating engine, andits converse a pump, a means for relieving the piston and cylinder wallof side'thrust and at the same time reducing the friction of thereciprocating parts, to lighten the weight of the reciprocating parts,to secure quick reversalv of the piston at the head end of its stroke,

and secure improved balance in the case of an engine having amultiplicity of cylinders. The nature of the invention is fullyexplained in the following description of a specific embodiment thereofand by drawings forming a part of this specification.

In' the drawings,-

Figure 1 is a section of so much of a reciprocating engine of theinternal combustion type as is necessary to eXplain the principles ofthe invention.

Figs. 2 and 3 are sectional detail views taken on the lines 2--2 and 33, respectively, of Fig. l.

In Fig. l, t represents one of. the cylinders of an internal combustionengine,'and typilies any engine cylinder in which a piston is arrangedto reciprocate. b represents the crank shaft, c represents the crank-pinwhich is carried by webs or arms ai. e is a piston rod which isconnected with the reciprocating piston by a knuckle or hin e joint andis made fast to ai wrist-pin f. Sald wrist-pin is contained in a bearingg in one end of a connecting rod h, the other end of the crank c.

the

The connecting rod t has a lateral arm y' which is connected by a pivotp-in 7c with a link Z having its opposite end anchored by a pivot pin min the frame.

n represents a crank case or equivalent structure hnusing the partsabove describedv Patented Nov. 29, 1192i.

through a slot o in the bearing sleeve and is threaded into thewrist-pin, being anchored therein byl a locking pin p. The slot o has anangular length slightly greater than the angle through which theconnecting rod swings aboutthe wrist-pin.

The arm j which projects laterally from the wrist-end 0f the connectingrod 1s preferably composed of two arms or webs,'as shown inlTig. 3,receiving the end of the guiding link between them and havin holesalined with a cross passagethrough t e end of the link in which thepivot pin 7c is seated the latter having a head on one endand a nut (Ion the other end.

rllhe combined action of the guide link Z and the lateral arm j of theconnecting rod has an important effect in guiding the wristpin in a pathvery close to the axial line of the cylinder; a path which is nearer toa straight line than is the arc in whlch the pivot pin c swings. riheaxis of the-crankshaft is set over to one side of the center line of thecylinder toward the pivot of the guide link, and this arrangementcontributes to the' effect just described.'v This fact 1s clearlyapparent from Fig. l, where C-l] represents the center line of thecylinder and A the aXis of the crank-shaft.

The character of the relative motion of the piston, wrist-pin, crank-pinand guide link pivot 7c is diagrammatlcally analyzedln Fig. 1. In thisdiagram the points designated by the letter f with exponents runningconsecutively from 1 to 13 are the positions of the wrist-pin centerWith equal Stages 0f the piston travel from one end of its stroke jspacing of the shows that the reversal of the taches the connecting rodarm to the other. rlhe points designated by the letter 7c, with similarexponents, indicate corresponding positions of the pivot which atto theguide link, and the points indicated by the letter c, with similarexponents, designate corresponding positions of the crank-pin. rl`heclose approximation of the pathv of the wristpin to a straight line isshown by the posi- -tion of the points f1, f2, etc., With relation tothe center line C-L, and it is apparent that there is less displacementof any of these points from such line than the displacement of thepoints k1, k2, etc., from Va straight line midwa between and parallel tothe chord of arc 701, 1013, and the tangent to the central point of saidarc. vThe comparatively close points 01, c2, 03, as compared with thespacing of the points, c, cl2, 013, piston travel at ,the head end ofits stroke occurs, and that its speed in the working stroke becomesapproximately equal to that of the crank-pin, during a relatively shortproportional part of' the rotation of the shaft; while a comparativelylong dwell of the piston occurs when the crank-pin crosses the deadcenter at the end of the working stroke.

As compared With the ordinary type of Y internal combustion engine, inwhich the connecting rod joins the piston and crankpin directly, thereis a quicker Areversal of the piston at the end of the compressionstroke and beginning of the working stroke, a quicker'acceleration ofthe piston speed, and a longer dwell between the end of the Workingstroke-and beginning of the exhaust stroke. These actions result ingreater thermal eiiiciency and give greater opportunity for scavengingthe cylinder of ex-v haust gases. The improved scavenging effect isparticularly marked when the invention isapplied to a two cycle engine.

A great gain in mechanical eiiiciency results from the closeapproximation of the wrist-pin travel to the center line, becausethereby substantially all .side thrust of the piston on the cylinder iseliminated, and the gain derived from this elimination is not offset toany considerable extent by the friction of the pivots m and c. Indeed,the loss of power 'absorbed in the friction of these parts is much lessthan that of a.Y sliding cross-headand the guide link is lighter inWeight and simpler than a cross-head and its guides. Inasmuch as ythestresses 'applied to the guide link are almost wholly tensile stressesand there is substantially no compression stress applied to it at anytime, the link may be made light in weight and at the same time havesufficient stilness. The connecting rod, being short, is comparativelylight in weight, and the mode of connecting 1t with the link by a 'pivotpin at Lacasse one side of the Wrist-pin relieves thek Wristpin ofstresses and wear except those due to the thrust of the piston.

lt Will be appreciated from the foregoing explanation that the inventionhas resulted in the provision of an engine having greater thermal andmechanical efficiency, lighter reciprocating parts, and less vibrationthan engines of the sort heretofore used.

What l claim and desire to secure by Let-y ters Patent is:

l. An engine comprising a cylinder, piston, piston rod, crank,connecting rod and guide link, the connecting rod having a lateral armbeside the Wrist-connection and lateral arm being pivoted to the guide2. In an engine, a cylinder, a crank, a pisyton reciprocating in thecylinder, a piston rod projecting Jfrom said piston, a connecting rodbetween the crank and piston rod and having a wrist-connection with thelat-y pivot at one side of the center line of the cylinder and thecionnecting rod having a laterally projecting arm beside the Wristconnection which is pivoted to said link, and the crank being set at'one side of thecylinder center line toward the pivot of the link.

4:. In an engine having a cylinder, a reciprocating piston, a revolvingcrankfa piston rod projecting from the piston, and a connecting rodbetween said crank and piston rod and having a wrist connection with thelatter, a means for guiding said wrist connection in a path in closeapproximation to the center line of the cylinder, comprising a lateralarm projecting from the connectin rod beside the Wrist connection, and aguide link pivoted to said lateral arm and having a fixed pivot support.

5. In an engine having a cylinder, piston and piston rod and crank, aconnecting rod having bearing boxes at its ends, one of which boxes isadapted to receive a wrist pin attached to the connecting rod, separatearms projecting laterally from the connecting rod adjacent to saidlast-named bearing box, a( link having an eye at one end containedbetween said arms, a pivot pin passing through said arms and interposedeye, and a fixed pivot engaged with said link at a point remote fromsaid pivot pin.

6. An engine comprising a cylinder, a piston, a crank, a connecting rod,a piston rod jointed to the connecting rod by a4 wrist joint, a pivotedguide link, and a connection between the guide link and connecting rod.

ieazeo arranged to compensate for the arc in which pivot joint betweenthe connecting rod and said link swings during the working stroke saidlink at the same side of the path in and to cause'travel of theWrlstjoint in a which the Wrist joint travels, and at such a path havinga closer approximation than distance from said path as to makethat path15 said arc to a straight line. a closer approximation to' a straightline 7. A11 engine comprising a cy1inder,a pisthan is the arc in whichsaid` pivot joint ton, a crank, aconnecting rod, a piston rod swings.

jointed to the connecting rod by` a Wrist In testimony whereof I haveaiiixed m joint, a guide linkpivotaily supported at a signature.

point at one side of the approximate midstroke position of the wrist.joint, and a EUGENE A. FORD.

